Au-doped polyacrylonitrile-polyaniline core-shell electrospun nanofibers having high field-effect mobilities

Au-doped polyacrylonitrile–polyaniline core–shell nanofibers are fabricated via electrospinning and subsequent gas-phase polymerization, providing a very high field-effect mobility of up to 11.6 cm² V⁻¹ s⁻¹. This method is also suitable for other conducting polymers and may eventually lead to a new and simplified fabrication of high-performance polymer organic field-effect transistors.

Migrant mobilities: cruel optimism and the case of AJ D’Cruz

Migrants are mobile by definition. They literally uproot themselves and move to sometimes-distant lands for a variety of reasons. Some move away from real or imagined threats to their very existence. Others seek a better quality of life. And some adventurous souls are inhabited by a restless wanderlust – a desire to roll the dice and see what happens. Such mobility requires fortitude and faith. Migrants move through space and, if they have an aspirational disposition, they attempt to accumulate symbolic capital to move up those social and economic hierarchies that bestow status and prestige within their adopted homes. The migrant journey to Australia often ends with the realisation that one has to make and re-make one’s identity, and perform a series of adjustments – adjustments in terms of comportment, dress, accent and disposition. My father was a migrant to Australia. More specifically, he was an Anglo-Indian migrant – a member of the ‘mixed-race’ community produced by British colonialism. He left India for the UK in 1962 and, after living in London for 10 years or so, immigrated to Australia in 1973, dragging his immediate family with him. Lured to the so-called ‘lucky country’ by the optimistic prospect of building wealth and prosperity under the Southern Cross, his ambitions were thwarted by casual and institutional racism. He died prematurely at the age of 53. This multi-media presentation tells his story through a series of encounters with the historical archive and the material remnants of my father’s relatively short life (letters, photographs, sound recordings, 8mm films). It provides a singular account of the performance practices involved in becoming a ‘New Australian’. Combining personal anecdotes and philosophical ruminations on history, technology, and cultural identity, the performance interrogates and performs a series of migrant mobilities.

Solid state NMR characterization of lithium conducting ceramics

⁷Li solid state NMR has been used to characterize lithium aluminium titanium phosphate and lithium lanthanum titanate ceramics. Both materials have high ionic mobilities at room temperature and this is reflected in their static ⁷Li powder patterns. In the case of the phosphate based ceramic, a narrow Lorentzian peak is observed above 300 K, which narrows further with increasing temperature. The accompanying quadrupolar structure, with C_Q (quadrupolar coupling constant) ~ 40 kHz, suggests that the lithium ions are hopping rapidly between equivalent, high electric field gradient sites. The ²⁷Al and ³¹P magic angle spinning (MAS) spectra reveal an asymmetric phosphorus peak and two distinct aluminium resonances. The room temperature powder pattern of Li_0.33La_0.57TiO₃ shows a dipolar broadened peak which narrows quite suddenly at 310 K revealing quadrupolar satellites with C_Q ~ 900 Hz. A second lithium site is also observed in this material, as indicated by a further, weaker quadrupolar structure (C_Q ~ 40 kHz).

Nonadditivity of faradaic currents and modification of double layer capacitance in the voltammetry of mixtures of ferrocene and ferrocenium salts in ionic liquids

Electrochemical studies on the Fc + e− Fc+ (Fc = ferrocene) process have been undertaken via the oxidation of Fc and reduction of Fc+ as the hexafluorophosphate (PF6−) or tetrafluoroborate (BF4−) salts and their mixtures in three ionic liquids (ILs) (1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium hexafluorophosphate). Data obtained at macro- and microdisk electrodes using conventional dc and Fourier-transformed large-amplitude ac (FT-ac) voltammetry reveal that diffusion coefficients for Fc and Fc+ differ significantly and are a function of the Fc and Fc+ concentration, in contrast to findings in molecular solvents with 0.1 M added supporting electrolyte media. Thus, the Faradaic currents associated with the oxidation of Fc (Fc0/+) and reduction of FcPF6 or FcBF4 (Fc+/0) when both Fc and Fc+ are simultaneously present in the ILs differ from values obtained when individual Fc and Fc+ solutions are used. The voltammetry for both the Fc0/+ and Fc+/0 processes exhibited near-Nernstian behavior at a glassy carbon macrodisk electrode and a platinum microdisk electrode, when each process was studied individually in the ILs. As expected, the reversible formal potentials (E°′) and diffusion coefficients (D) at 23 ± 1 °C were independent of the electrode material and concentration. However, when Fc and FcPF6 or FcBF4 were both present, alterations to the mass transport process occurred and apparent D values calculated for Fc and Fc+ were found to be about 25−39% and 32−42% larger, respectively, than those determined from individual solutions. The apparent value of the double layer capacitance determined by FT-ac voltammetry from individual and mixed Fc and Fc+ conditions at the GC electrode was also a function of concentration. Double layer capacitance values increased significantly with the concentration of Fc and FcPF6 or FcBF4 when species were studied individually or simultaneously, but had a larger magnitude under conditions where both species were present. Variation in the structure of the ILs and hence mobilities of the ionic species, when Fc and FcPF6 or FcBF4 are simultaneously present, is considered to be the origin of the nonadditivity of the Faradaic currents and variation in capacitance.

Identification of tRNAs incorporated into wild-type and mutant human immunodeficiency virus type 1

We have identified the tRNAs which are incorporated into both wild-type human immunodeficiency virus type 1 strain IIIB (HIV-1IIIB) produced in COS-7 cells transfected with HIV-1 proviral DNA and mutant, noninfectious HIV-1Lai particles produced in a genetically engineered Vero cell line. The mutant proviral DNA contains nucleotides 678 to 8944; i.e., both long terminal repeats and the primer binding site are absent. As analyzed by two-dimensional polyacrylamide gel electrophoresis, both mutant and wild-type HIV-1 contain four major-abundance tRNA species, which include tRNA(1,2Lys), tRNA(3Lys) (the putative primer for HIV-1 reverse transcriptase) and tRNA(Ile). Identification was accomplished by comparing the electrophoretic mobilities and RNase T1 digests with those of tRNA(3Lys) and tRNA(1,2Lys) purified from human placenta and comparing the partial nucleotide sequence at the 3' end of each viral tRNA species with published tRNA sequences. Thus, the absence of the primer binding site in the mutant virus does not affect tRNA(Lys) incorporation into HIV-1. However, only the wild-type virus contains tRNA(3Lys) tightly associated with the viral RNA genome. The identification of the tightly associated tRNA as tRNA(3Lys) is based upon an electrophoretic mobility identical to that of tRNA(3Lys) and the ability of this RNA to hybridize with a tRNA(3Lys)-specific DNA probe. In addition to the four wild-type tRNA species, the mutant HIV-1-like particle contains two tRNA(His) species and three tRNA-sized species that we have been unable to identify. Their absence in wild-type virus makes it unlikely that they are required for viral infectivity.

Effects of modifying the tRNA(3Lys) anticodon on the initiation of human immunodeficiency virus type 1 reverse transcription

tRNA(3Lys) is a primer for reverse transcription in human immunodeficiency virus type 1 (HIV-1), and the anticodon of tRNA(3Lys) has been implicated in playing a role in both its placement onto the HIV-1 genome and its interaction with HIV-1 reverse transcriptase (RT). In this work, the anticodon in a tRNA(3Lys) gene was changed from UUU to CUA (tRNA(3Lys)Su+) or, in addition, G-73 was altered to A (tRNA(3Lys)Su+G73A). COS-7 cells were transfected with either wild-type or mutant tRNA(3Lys) genes, and both the wild-type and mutant tRNA(3Lys) produced were purified by using immobilized tRNA-specific hybridization probes. Each mutant tRNA(3Lys) was tested for its ability to prime reverse transcription in vitro, either alone or in competition with wild-type tRNA(3Lys). Short RT extensions of wild-type and mutant tRNALys could be distinguished from each other by their different mobilities in one-dimensional single-stranded conformation polymorphism polyacrylamide gel electrophoresis. These reverse transcription products show that heat-annealed tRNA(3Lys)Su+ has the same ability as heat-annealed wild-type tRNA(3Lys) to prime RT and competes equally well with wild-type tRNA(3Lys) for priming RT. tRNA(3Lys)Su+G73A has 60% of the wild-type ability to prime RT but competes poorly with wild-type tRNA(3Lys) for priming RT. However, the priming abilities of wild-type and mutant tRNA(3) are quite different when in vivo-placed tRNA is examined. HIV-1 produced in COS cells transfected with a plasmid containing both the HIV-1 proviral DNA and DNA coding for tRNA(3Lys)Su+ contains both endogenous, cellular wild-type tRNA(3Lys) and mutant tRNA(3Lys). When total viral RNA is used as the source of primer tRNA placed onto the genomic RNA in vivo, only wild-type tRNA(3Lys) is used as a primer. If the total viral RNA is first heated and exposed to hybridizing conditions, then both the wild-type and mutant tRNA(3Lys) act as primers for RT. These results indicate that the tRNA(3Lys)Su+ packaged into the virions is unable to act as a primer for RT, and a model is proposed to explain the disparate results between heat-annealed and in vivo-placed primer tRNA.

One-dimensional polyelectrolyte/polymeric semiconductor core/shell structure : sulfonated poly(arylene ether ketone)/polyaniline nanofibers for organic field-effect transistors

A polyelectrolyte/polymeric semiconductor core/shell structure is developed for organic field-effect transistors (OFETs) based on sulfonated poly(arylene ether ketone)/polyaniline core/shell nanofibers via electrospinning and solution-phase selective polymerization. The polyelectrolyte does not work as a gate dielectric, but can provide an internal modulation from the nanointerface of the 1D core/shell nanostructure. The transistor devices display very high mobilities.

An Iranian migrant mother's production of selves through her family photograph collection

In researching migrant identities, visual methodology offers much promise and yet there is a marked lack of recent research that makes use of visual methods. Previous studies of migrant identities have privileged verbal representations of identities. Gillian Rose's (2010) work with mothers and their family photographs in the United Kingdom, in which she describes the role of family photographs in both producing social subject positions and in maintaining family togetherness across distances, is a useful model for research into the construction and negotiation of migrant identities.

The literature on family photography suggests that it is usually the woman/mother who takes on the role of making the family photograph album; of narrating the family's story (Rose, 2010; Holland, 2009; 1991; Chambers, 2003). The family photograph collection, together with the participant's interwoven verbal interpretation, is a particularly relevant data source for use in identity research as there is the potential for key themes of place, mobilities and space to be explored at new depth and from a feminist perspective.

This paper will report on an ethics approved study of one Iranian migrant mother and her family photograph collection, focusing on her representation of the identities and subjectivities of herself and her children through photographs taken following migration to Australia. The paper will consider the participant's family photographs as both visual objects and visual-verbal narratives produced within historically and culturally situated discourses. It will explore how photographs and oral interpretations cohere to enable migrant mothers to re/produce selves. The paper will examine the production of subject positions specifically in relation to place, mobilities and space.

The research is situated within critical visual ethnography and is informed by a reflexive feminist approach. The meaning making of the photographs under study will be explored at the sites of production, image, and audience. The combined visual-verbal methods used in this study aim to provide a new contribution to the literature on migrant identities and form the basis of a scaled up research design of a larger cohort of mothers.

Transiting with the environment: an exploration of traveller’s reorientations as creative and collaborative practice

Travellers undertake a process of reorientation and realignment that is particular to each destination. This process intensifies when travelling long distances across borders, cultures and climates, as travellers utilise performative, embodied and creative methods that respond to each new environment. Certain destinations, such as those with unique and extreme natural environments, induce a socio-cultural imaginary that primes travellers for what kind of experience they might have. Large, immersive landscapes and climates congeal with expectations of what each destination requires in order to navigate through it. Common bearings of distance and scale are skewed, as travellers are positioned within areas of vastness. In these moments immersive experiences contrast with daily processes, such as the act of packing a bag, as this heightened sensory awareness exacerbates the subtle material and spatial negotiations. Utilising interviews and photographic documentation of travellers to Iceland and Nepal, this paper develops the proposal that certain destinations intensify our attunement to these moments of reorientation, facilitating situated and creative methods.

As recent developments in the fields of mobilities and tourism draws attention to material interactions during travel, and current ‘new materialism’ movements in theory and practice reveal alternative affective methods of engagement, an exploration of interactions with/in immersive sites is needed in order to evaluate the potential that these kinds of transitions offer everyday experiences of movement. Nigel Thrift’s proposition of Non-Representational Theory provides clarity on the ways in which spatial awareness influences such transitions and environmental experiences. Using his acknowledgement of a more ontologically driven responsiveness to space, this permits a shift away from the presupposed containment of spaces as isolated destinations, toward a relational spatiality that encompasses all actors – including environments – as vital elements in the generative processes of situating our movements.

Creative strategies that afford sensory, aesthetic and embodied performances provide ways to examine these experiences, providing a multitude of possibilities as individual experiences shift towards collective and collaborative performances, as we are immersed within a range of human and non-human actors. This paper explores the transition away from ‘consuming’ environments, and advocates for the need to turn towards a situated collaboration with environments, propelling an awareness of sustainable and creative travel practices. An understanding of affirmative differences is required within travel cultures, rather than expressing transitions as confined within the ‘home’ versus ‘away’ dichotomy that lingers from elite western travel narratives. In order to undertake the many movements required, this paper draws on the theoretical approaches of sustainable nomadism as described by Rosi Braidotti to highlight the linkages of environmental and bodily experiences.

Through multidisciplinary literature, interviews and personal reflections, this paper proposes that certain destinations amplify processes of alignment with the environment, developing affective, embodied and situated experiences that overcome the human/non-human divide.

Intercultural pathways for knowledge Transfer within academic mobility

This paper focuses on academic mobility with the view of examining knowledge flows and effective cultural pathways for knowledge transfer. Its main objective is to set up the theoretical parameters for exploring intercultural encounters within academic mobility with an additional goal of revealing underlining conditions for effective intercultural knowledge transfer and creation. Academic mobility describes global mobilities of tertiary students and university staff and refers to a growing phenomenon worldwide. It creates additional possibilities for exploring the enabling conditions for the intercultural knowledge flows. Academic migrants have been acknowledged as important agents of intercultural knowledge transfer, interchange and, ultimately, knowledge creation. This paper is guided by a hypothesis that cosmopolitan dispositions can create preconditions for successful knowledge transfer in everyday intercultural interactions in academia. In this paper, theoretical notions and ideas are discussed to provide a foundation for designing an ethnographic research which will seek to analyse empirical manifestations of emerging cosmopolitanism. Some preliminary findings of a pilot study are also analysed.

On the strength of dislocation interactions and their effect on latent hardening in pure Magnesium

This study is dedicated to the quantification of latent hardening and its effect on the plasticity of pure hexagonal magnesium. To this end, discrete dislocation dynamics simulations are used to (1) extract latent hardening parameters coupling different slip systems, and to (2) assess the validity of two existing constitutive models linking slip system strength to dislocation densities on all slip systems. As hexagonal materials deform via activation of different slip modes, each with different mobilities and lattice friction stress, the effects of the latter on latent hardening evolution are also investigated. It is found that the multi-slip formulation proposed by Franciosi and Zaoui gives accurate predictions when multiple interactions are involved while the formulation suggested by Lavrentev and Pokhil systematically overestimates the flow stress. Similar to FCC materials, it is also found that collinear interactions potentially contribute the most to latent hardening. Basal/pyramidal c + a interactions are found to be very strong, while interactions involving second-order pyramidal c + a primary dislocations appear to be the weakest ones. Finally, the latent hardening parameters, extracted from the discrete dislocation dynamics simulations, are used in polycrystal simulations and the impact of finely accounting for latent hardening on predictions of the macroscopic anisotropic response is shown to be of significant importance.